WANG Zhen,ZHENG Xin,LIU Fei,WANG Pei,GAN Lin,WANG Jing-jing.Tandem organic light-emitting diodes with buffer- modified C60/pentacene as charge generation layer[J].Optoelectronics Letters,2017,13(5):325-329
Tandem organic light-emitting diodes with buffer- modified C60/pentacene as charge generation layer
Author NameAffiliation
WANG Zhen College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
ZHENG Xin College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
LIU Fei College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
WANG Pei College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
GAN Lin College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
WANG Jing-jing College of Optoelectronic Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, China 
Abstract:
      Buffer-modified C60/pentacene as charge generation layer (CGL) is investigated to achieve effective performance of charge generation. Undoped green electroluminescent tandem organic light-emitting diodes (OLEDs) with multiple identical emissive units and using buffer-modified C60/pentacene organic semiconductor heterojunction (OHJ) as CGL are demonstrated to exhibit better current density and brightness, compared with conventional single-unit devices. The current density and brightness both can be significantly improved with increasing the thickness of Al. However, excessive thickness of Al seriously decreases the transmittance of films and damages the interface. As a result, the maximum current efficiency of 1.43 cd.A-1 at 30 mA.cm-2 can be achieved for tandem OLEDs with optimal thickness of Al. These results clearly demonstrate that Cs2CO3/Al is an effective buffer for C60/pentacene-based tandem OLEDs.
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